Substitutionally rhodium(IV)-doped titania showing photocatalytic activity toward organics oxidation under visible-light irradiation

In this study, an aqueous solution containing rhodium(IV) (Rh(IV)) was prepared by oxidation of rhodium(III) (Rh(III)) with solid sodium bismuthate in nitric acid and then used as a medium for hydrothermal titania preparation to obtain rhodium-doped titania (Rh-TiO2) composite. Rh(IV) species were observed in Rh-TiO2 in XPS analysis. Effect of rhodium/titanium molar ratio (Rh/Ti) on the photocatalytic activity was studied. The obtained characteristics suggest successful rhodium substitution and doping of titania to give visible-light absorption. The Rh-TiO2 composite exhibits enhanced photocatalytic activity for acetic acid decomposition and 2propanol oxidation under UV-vis (> 290 nm) and visible-light (> 450 nm) irradiation, respectively. The enhanced photocatalytic activity is attributable to the visible-light absorption induced by rhodium doping. These results indicate that Rh-TiO2 photocatalyst materials could be promising materials for high-efficiency photooxidation reactions under visible-light irradiation.

Automated summary

In this study, a Rh-TiO2 composite material was prepared by oxidizing Rh(III) species to Rh(IV) in an aqueous solution, which showed enhanced photocatalytic activity. XPS analysis confirmed the presence of Rh(IV) species in the composite, and the effect of Rh/Ti molar ratio on the photocatalytic activity was studied, demonstrating that Rh doping improved the visible-light absorption and overall performance of the composite.